Dean opened the door and followed Jimmy outside.
“Hey, wait a minute!” he yelled.
Jimmy stopped and waited patiently for Dean to catch up with him.
“Where’s Cas? What did you do to him?” Dean asked trembling and furious.
“Don’t worry, he’s alive. He’s in here, somewhere. We switched places” Jimmy explained dark.
“I thought you were dead” Dean snapped hostile.
“Clearly you didn’t pay much attention. Castiel said I wouldn’t age or die. I’ve been stuck in my own body for ages and it’s time Castiel knows what that feels like” Jimmy replied bitter.
“But…how…?” Dean stammered.
“How did I regain control over my body?” Jimmy finished Dean’s unspoken question. “From the moment Castiel turned human I’ve attacked him from the inside”
Sam joined them. “Wait, you’re the one that gave him those headaches and stomach aches and fevers” he realized.
Jimmy smiled as if he were proud of himself.
“And I’m the one who forced him to take those painkillers and bash his head against the toilet. And I’m the one who let him OD on heroin” he added. “Now, if you don’t mind, I have a wife and daughter who need me”
He turned around, leaving Sam and Dean stunned.